Balancing Ni0 and Ni2+ on γ-Al2O3 for Efficient Steam Methane Reforming

Steam methane reforming (SMR) is the most mature technology for hydrogen production in industry, and alumina supported nickel (Ni/Al2O3) is the most widely used catalyst. Herein, the key role of Ni valence state on the catalytic SMR performance of Ni/Al2O3 is reported. The ratio of Ni-0/Ni2+ on Ni/Al2O3 is individually and effectively tuned by changing the reduction temperature after wet impregnation. Catalytic performance of Ni/Al2O3 is greatly dependent on the surface concentration of Ni-0 and Ni2+. The catalyst reduced at 675 degrees C possesses balanced Ni-0 and Ni2+ sites and exhibits superior catalytic performance, on which 60 % of methane is stably converted at 600 degrees C. CH4-TPD and CO-TPD profiles demonstrate that appropriate Ni-0/Ni2+ ratio can promote the adsorption of CH4 and inhibit the moderate-strength adsorption of CO, which leads to increased SMR activity and selectivity.

Automated summary

The Ni valence state on the surface of Ni/Al2O3 catalyst plays a crucial role in the catalytic performance of SMR. By tuning the Ni-0/Ni2+ ratio through reduction temperature control, the catalytic activity and selectivity of the catalyst can be greatly improved.